Many machines, including off-highway machines, are known to use hydrostatic drive systems to drive the ground engaging elements, such as wheels or tracks, of the machine. Such hydrostatic drive systems commonly include at least one pump driven by a prime mover, such as an internal combustion engine, of the machine. The pump may be configured to drive one or more sets of motors, which, in turn, power the ground engaging elements of the machine. The pump, and/or motors, may provide variable displacement, such that a fluid flow between the components of the hydrostatic drive system may be adjusted while the machine is running. As a result, direction, speed, and torque of the drive wheels may be continuously varied.
During a typical work cycle, an operator may choose to quickly change the direction, speed, and/or torque, as permitted by the hydrostatic drive system, in order to maximize efficiency in performance of the work cycle. For example, an operator may wish to drive toward a pile of materials at maximum speed, pick up a load of the materials, and quickly reverse away from the pile in order to transport the load to a new location. However, if the operator commands the hydrostatic drive system to accelerate, decelerate, or change directions too quickly, the components of the hydrostatic drive system may not be capable of suck quick transitions and, as a result, the machine may jerk or lug. This sacrifice of smoothness for speed may result in a reduction of efficiency caused by, for example, discomfort and fatigue of the operator and/or spilling a portion of the load. Thus, operators may desire a balance of quick responsiveness of the hydrostatic drive system with smoothness in transitions of the hydrostatic drive system.
U.S. Pat. No. 7,958,725 to Elliott teaches a method for effecting simultaneous displacement changes in a hydrostatic drive system. The method includes determining a total displacement change required for rotary fluid actuators of the hydrostatic drive system to produce a desired gear ratio change. If the total displacement change is above a predetermined threshold, displacements of the rotary fluid actuators are simultaneously changed. However, if the total displacement change is below a predetermined threshold, the displacements of the rotary fluid actuators are sequentially changed.
The present disclosure is directed to one or more of the problems or issues set forth above.